RegularExpressionValidator有效，但RequiredFieldValidator无效

Question

I am trying to set RegularExpressionValidator and RequiredFieldValidator for my textbox in an asp.net web form. My RegularExpressionValidator works and give the error message but my RequiredFieldValidator does not show the error message when I click the submit button. I have also tried adding ValidationGroup to my textbox and button and RegularExpressionValidator and RequiredFieldValidator, but nothing changed. Could you please help we with it? By the way I have already added

<appSettings>
      <add key="ValidationSettings:UnobtrusiveValidationMode" value="None" />
    </appSettings>

to my webconfig. Thank you.

<input type="text" id="user" placeholder="username" runat="server"/>
            <asp:RegularExpressionValidator  runat="server"  ErrorMessage="Username is not suitable" Display="Dynamic"
                 ValidationExpression="^([a-zA-Z0-9]{0,8})$" ID="req1"
                ForeColor="Red" ControlToValidate="user" />
            <asp:RequiredFieldValidator runat="server" Display="Dynamic" ErrorMessage="Username required" ID="req2"
                ForeColor="Red" ControlToValidate="user"/>
 <button id="submitbtn" type="button" runat="server">Sign up</button>  

Answer 1

Try this

Username: <input type="text" id="user" name="usrname" required>
<input type="submit" id="submitbtn" type="button" runat="server"/>
        <asp:RegularExpressionValidator  runat="server"  ErrorMessage="Username is not suitable" Display="Dynamic"
             ValidationExpression="^([a-zA-Z0-9]{0,8})$" ID="req1"
            ForeColor="Red" ControlToValidate="user" />
        <asp:RequiredFieldValidator runat="server" Display="Dynamic" ErrorMessage="Username required" ID="req2"
            ForeColor="Red" ControlToValidate="user"/>

Answer 2

You can fix the issue by adding the 'onclick' eventhandler for the button as below:

<button id="submitbtn" type="button" runat="server" onclick="javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(&quot;ctl00$MainContent$submitbtn&quot;, &quot;&quot;, true, &quot;&quot;, &quot;&quot;, false, false))">Sign up</button>

OR

Use Asp.Net button control, which will have the onclick handler rendered by Asp.Net. <asp:Button ID="submitbtn" Text="Sign up" runat="server" />

Seems like only if 'WebForm_DoPostBackWithOptions' function is invoked, validation will fire.

Answer 3

oh buddy,you have made a typo mistake,type must be submit

<button id="submitbtn" type="submit" runat="server">Sign up</button>

Type="submit" will post the page back to the server whereas type doesnt post the page to the server.

Another way is using Page.isValid property.